diff options
Diffstat (limited to 'kernel/vmemitcodes.ml')
| -rw-r--r-- | kernel/vmemitcodes.ml | 22 |
1 files changed, 17 insertions, 5 deletions
diff --git a/kernel/vmemitcodes.ml b/kernel/vmemitcodes.ml index c1d8fcb855..d3af8bf09b 100644 --- a/kernel/vmemitcodes.ml +++ b/kernel/vmemitcodes.ml @@ -135,6 +135,16 @@ let out env opcode = let is_immed i = Uint63.le (Uint63.of_int i) Uint63.maxuint31 +(* Detect whether the current value of the accu register is no longer + needed (i.e., the register is written before being read). If so, the + register can be used freely; no need to save and restore it. *) +let is_accu_dead = function + | [] -> false + | c :: _ -> + match c with + | Kacc _ | Kenvacc _ | Kconst _ | Koffsetclosure _ | Kgetglobal _ -> true + | _ -> false + let out_int env n = out_word env n (n asr 8) (n asr 16) (n asr 24) @@ -327,8 +337,6 @@ let emit_instr env = function if Int.equal n 0 then invalid_arg "emit_instr : block size = 0" else if n < 4 then (out env(opMAKEBLOCK1 + n - 1); out_int env t) else (out env opMAKEBLOCK; out_int env n; out_int env t) - | Kmakeprod -> - out env opMAKEPROD | Kmakeswitchblock(typlbl,swlbl,annot,sz) -> out env opMAKESWITCHBLOCK; out_label env typlbl; out_label env swlbl; @@ -349,8 +357,7 @@ let emit_instr env = function if n <= 1 then out env (opGETFIELD0+n) else (out env opGETFIELD;out_int env n) | Ksetfield n -> - if n <= 1 then out env (opSETFIELD0+n) - else (out env opSETFIELD;out_int env n) + out env opSETFIELD; out_int env n | Ksequence _ -> invalid_arg "Vmemitcodes.emit_instr" | Kproj p -> out env opPROJ; out_int env (Projection.Repr.arg p); slot_for_proj_name env p | Kensurestackcapacity size -> out env opENSURESTACKCAPACITY; out_int env size @@ -375,7 +382,9 @@ let rec emit env insns remaining = match insns with | (first::rest) -> emit env first rest) (* Peephole optimizations *) | Kpush :: Kacc n :: c -> - if n < 8 then out env(opPUSHACC0 + n) else (out env opPUSHACC; out_int env n); + if n = 0 then out env opPUSH + else if n < 8 then out env (opPUSHACC1 + n - 1) + else (out env opPUSHACC; out_int env n); emit env c remaining | Kpush :: Kenvacc n :: c -> if n >= 0 && n <= 3 @@ -397,6 +406,9 @@ let rec emit env insns remaining = match insns with | Kpush :: Kconst const :: c -> out env opPUSHGETGLOBAL; slot_for_const env const; emit env c remaining + | Kpushfields 1 :: c when is_accu_dead c -> + out env opGETFIELD0; + emit env (Kpush :: c) remaining | Kpop n :: Kjump :: c -> out env opRETURN; out_int env n; emit env c remaining | Ksequence c1 :: c -> |